I’m surprised at how surprised you were by your sister’s compliment, I mean your comic is good. I mean, I’m still laughing at the Sarah Palin lookalike.
On a related note, yes, stats uses calculus (extensively.) Basically, calculus is great for finding areas underneath a graph, so if you are creating an equation that needs to have an area underneath the curve of 1 even if you go to infinity in the x-axis (infinity is weird) since all possible probabilities have to add up to 1, then calculus helps you not only come up with that equation, but it helps you find out the area underneath the curve at certain points, which gives you a certain probability.
It’s funny, I wanted to learn how to draw and make a webcomic until I took my first drawing class and learned I nearly didn’t have NEARLY enough patience or attention span, so I took up math, since I’m (somewhat) good at it and I can focus on puzzles; it’s kind of nice to know that the stuff I’m learning is useful and isn’t stuff that everyone already knows.